Now, the bulb packaging, depending on which ones you buy, say they're guaranteed for anywhere between 2-8 years. We consistently have to replace all of ours (we have 2 fixtures with 4 bulbs each) every 4 months or so.
The fixtures were installed by an electrician hired by the woman who sold us the house, and we've since discovered that she's a bit of a tightwad. Is it likely that she the guy she hired installed the fixtures improperly?